I have a 77 camper with 74 1.8 that has been converted to a weber progressive, (mine finally runs good so don't try to convert me now!) Anyways, I've been meaning to hook up a fuel pump relay for safety reasons to my electric fuel pump. My firewall looks like this, except it is missing both white harness'/plugs on the right.

I only have the one plug connected on the left. First of all, what does this hooked up one do? Also, can I use what looks like a relay (the middle empty plug) to switch my fuel pump? What about the far right plug? I no longer have the booster fan either...Can I hook up a OG booster fan with a single weber setup? Is it worth it? Additional cooling? Sorry for the many questions, any help is greatly appreciated._________________

Tom Powell wrote:

Olddog52 wrote:

one tab to ground, the other to a 12 volt source. Listen intently for a sound.

I put the horn next to my ear and I could hear the ocean.
When I hooked up the battery I couldn't hear anything for three days.

1977 Westfalia with a 1974 1800 Type 4 engine

Last edited by shaunone on Sat Aug 27, 2011 3:07 pm; edited 1 time in total

Are you just looking for something to do or trying to solve an issue, and if so what is it?_________________It is a 40 to 50 year old car that has been abused by at least one of the prior owners. Many parts are no longer available, and like BusDaddy says - rust never sleeps. Better get used to it, or if you can't then pull your wallet, and your tools out.

Sorry guys, maybe I should've been a little more clear. I want to install a safety relay for my electric fuel pump. Right now the pump is hardwired to the coil. I was going to buy a generic relay at the FLAPS for this purpose. Then I noticed this empty relay in my engine compartment. Can I use this relay for the same purpose? It looks like a double relay, and the other is being used. What is the other side being used for? Can I use the empty side without affecting the side that is hooked up?_________________

Tom Powell wrote:

Olddog52 wrote:

one tab to ground, the other to a 12 volt source. Listen intently for a sound.

I put the horn next to my ear and I could hear the ocean.
When I hooked up the battery I couldn't hear anything for three days.

I guess I'll just buy a cheap relay from CT and forget about this whole double relay thing...

It would be easier. What you want to do could be done but most likely none of us have the time to design and walk you through it. Not only that but you have no guarantee that the reason the FI got pulled off was a bad double relay and the mechanic didn't know how to troubleshoot it so a carb went on. Using a new relay would be a good thing. Now the downside - if the relay sticks the fuel pump will stay on. Might be better to put a real switch under the dash that turns it on and run that through the ignition switch as well. If it is not obvious it becomes a cheap alarm kill too. Let's a thief drive far enough to get away from you and then it dies on him so you are out of danger._________________It is a 40 to 50 year old car that has been abused by at least one of the prior owners. Many parts are no longer available, and like BusDaddy says - rust never sleeps. Better get used to it, or if you can't then pull your wallet, and your tools out.

That's interesting, because the only reason I wanted to install one was because everyone on here suggests a relay. But like you say, if the relay sticks you could cause big problems as well. So you are thinking that a guy should install an actual switch AND a relay? That way the relay doesn't stick while you're parked overnight and fill the whole block with gas?_________________

Tom Powell wrote:

Olddog52 wrote:

one tab to ground, the other to a 12 volt source. Listen intently for a sound.

I put the horn next to my ear and I could hear the ocean.
When I hooked up the battery I couldn't hear anything for three days.

That's interesting, because the only reason I wanted to install one was because everyone on here suggests a relay. But like you say, if the relay sticks you could cause big problems as well. So you are thinking that a guy should install an actual switch AND a relay? That way the relay doesn't stick while you're parked overnight and fill the whole block with gas?

Yes - the idea is to get the load off the ignition switch.

You can have the best of all world if you want. Run a line from the accessory position on the ignition to the energizing coil on the relay. Then run a fused "always-on" wire from the fuse box through the relay points through the kill switch then back to the pump. That takes the load off the ignition switch and also gives you a permanent kill when you are out of the bus. It also makes it so if someone hotwires the bus to steal it they only drive as far as the fuel in the bowl will take them.

Relys don't often weld points shut but it does happen. They also fail the other way sometimes and refuse to make contact between the points. I have seen three position switches used where center is off. 1 side is power from the ignition switch thru a relay and the other side is power through the ignition switch without the relay._________________It is a 40 to 50 year old car that has been abused by at least one of the prior owners. Many parts are no longer available, and like BusDaddy says - rust never sleeps. Better get used to it, or if you can't then pull your wallet, and your tools out.

Put the double relay, resistor block, and other old FI parts up in the classifieds so that other FI folks can use them._________________John
"The bus came by and I got on. That's when it all began..." - Garcia/Weir/Kreutzman
http://vw.tauxe.net

Find a FUEL PUMP RELAY from an early Rabbit, etc and use that. It has an additional input from the ignition circuit- if the engine stops, so does the pump. I assume it has a logic circuit in it for 2 inputs. Check a wiring diagram for water cooled cars and follow suit. Thats what I did. It is no more work than using a generic relay and screwing around trying to emulate the real deal. If you can find one in the boneyard you can get the socket also, should be cheap or free, depending on yard personnel, customer attitude, moon phase, etc. _________________Sent from a white van down the street.

Hi if I understand you right your primary concern is safety. A relays purpose is to control a large current (your pump) with a small current (your ignition switch). That being said. Your driving along and pow, you get hit. Your rendered unconscious. The engines stopped, but the Ign. key is still on, the fuel pump is pouring fuel onto a already lit fire. You need to wire in a Inertia switch or oil pressure switch . This will shut the pump down in the event of an accident. Good Luck hope this helps.

Last edited by Tcash on Sun Aug 28, 2011 2:07 pm; edited 1 time in total

Or wire a relay coil from ground to the blue wire going to the alternator / generator regulator. When the generator is putting out power, the relay will activate. You would wire the relay contacts to provide power to the fuel pump. Thus, if the engine stops, so should the fuel pump.

I'd supply a bypass switch in case of generator failure, so you won't be stranded.

Ref: aux blower on late type 4 engine bays uses the same setup._________________'71 panel, now with FI

'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones

To steal ideas from one person is plagiarism; to steal from many is research - Steven Wright

In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh

It is impossible for a man to learn what he thinks he already knows - Epictetus

Hi if I understand you right your primary concern is safety. A relays purpose is to control a large current (your pump) with a small current (your ignition switch). That being said. Your driving along and pow, you get hit. Your rendered unconscious. The engines stopped, but the Ign. key is still on, the fuel pump is pouring fuel onto a already lit fire. You need to wire in a Inertia switch or oil pressure sensor . This will shut the pump down in the event of an accident. Good Luck hope this helps.

I goofed, it is not a Oil Pressure Sensor. Correction Oil Pressure Switch Sorry I will make the correction.